The present invention relates to video tape cassettes and to devices for use in connection therewith.
In recent years, video tape recording and playback equipment particularly designed for non-commercial, in-home use has become available on a relatively broad scale and has come into widespread use due in large part to the development and refinement of a convenient cartridge-type housing for video recording tape in which a selected length of video tape is permanently stored on reels for recording and playback use, characteristically referred to as video tape cassettes, and to the development and refinement of compatible machines adapted to accept such tape cassettes both for the recording of video signals on the tape thereof and for the viewing of video signals previously recorded thereon. One potential disadvantage of the dual function of such machines for recording and playback is the possibility of inadvertently recording a new video signal onto the tape of a cassette over a previously recorded signal thereon.
As a safeguard against such overrecording occurring unintentionally, the housing of a conventional tape cassette is provided with a small opening therein and conventional recording and playback machines are provided with a sensing arrangement adapted to render the machine inoperative in its record mode when such opening is sensed but to permit operation in the record mode when no opening is sensed. Accordingly, blank tape cassettes are constructed with a removable tab within the antirecording opening thereof to permit initial use of the cassettes for recording of video signals on the tape thereof and to permit the permanent storage for playback purposes of signals recorded thereon upon the removal of the tab. Conversely, tape cassettes initially pre-recorded by the producer have no tab or other obstruction in the antirecording opening, the tab being removed following the completion of recording as part of the production process. While the advantages provided by this manner of construction of tape cassettes and their compatible playing and recording machinery is readily apparent, certain disadvantages therein exist in that the removal of the tab in the antirecording opening essentially renders the tape cassette unusable thereafter for recording. Thus, if one ever desires to overrecord on a tape cassette the tab of which has been removed, it is necessary to circumvent in some way the antirecording opening such as, for example, by placing ordinary adhesive tape over the opening, the usual manner in which this result is achieved.
In contrast, the present invention provides a device which may be readily attached to existing tape cassettes or may be incorporated in new tape cassettes in the manufacture thereof and is adapted to be movable on the cassette, rather than removable therefrom, to selectively close and open the antirecording opening thereof as is desired.